Ecological significance of plant biomass turnover

植物物种的分布在很大程度上取决于它们对不同生境环境条件的适应能力，例如养分、水和光的可用性。在这方面，植物获得这些资源的能力是一个重要的、已被充分研究的特征。同样重要但研究较少的是植物避免一旦获得的资源损失的能力，即其生物质周转率。资源获取与生长速度密切相关，资源损失与叶和根的寿命密切相关。生长速度和器官寿命之间通常存在着相反的关系：生长迅速的植物通常长出的叶子和根很短。这个项目的目的是调查在生长和寿命之间权衡的潜在因素，以及在不同环境中对物种表现的影响。调查中包含的环境因素有生产力、干扰率和生长季长度。该计划包括园艺实验和田间实验。对植物结构的短期研究将与关于物种之间相互作用的长期实验相结合。该计划的一个重要方面是，根将包括在调查中。在草本植物群落中，根往往占生物量的50%以上，但在植物生长策略的研究中往往被忽视。该项目解决了有关生态和进化机制的基本问题，但对于理解土地利用和气候变化的后果也具有潜在的重要意义。植被的生物量周转特征对生态系统中的养分和碳循环有重要影响。例如，对生长季长度和生物量周转率之间关系的洞察对于我们理解气候变化中土壤中的碳固存是至关重要的，这是履行《京都协定》措施的一个重要方面。

The distribution of plant species is largely determined by their ability to cope with the environmental conditions in different habitats, conditions such as the availability of nutrients, water and light. A plant's ability to acquire these resources is in this respect an important and well-studied trait. Equally important, but less studied, is the plant's ability  to avoid losses of the once acquired resources, i.e., its biomass turnover rate. Resource acquisition is closely related to growth rate; resource loss to life span of leaves and roots. There is generally a reverse relationship between growth rate and organ life span: plants which grow fast usually produce short-lived leaves and roots. The aim of this program is to investigate factors underlying the tradeoff between growth and lifespan, and the consequences for species' performance in different environments. Environmental factors included in the investigations are productivity, rate of disturbance and growing season length. The program consists of garden and field experiments. Short-term investigations of plant structure will be combined with long-term experiments about interactions between the species. An important aspect of the program is that roots will be included in the investigations. In herbaceous communities roots often make over 50% of the biomass production, but are frequently neglected in studies about plant growth strategies. This program addresses basic questions about ecological and evolutionary mechanisms, but it is also potentially important for understanding the consequences of changes in land use and climate. Biomass turnover characteristics of vegetation strongly influence nutrient and carbon cycling in ecosystems. Insight, for example, in the relationship between growing season length and biomass turnover rate is essential for our understanding of carbon sequestration in soils in a changing climate, an important aspect with respect to measures to fulfill the Kyoto agreement.